1. Areas of Industrial Application
This invention relates to a flexible substrate, electro-optical device and electronic equipment.
2. Prior Art
Electro-optical devices represented by display devices such as a liquid crystal display and an EL (electro luminescence) display are being widely utilized in various types of electronic equipment. In this type of electro-optical device, a composition, where an IC chip generating the signals to drive the electro-optical substances such as a liquid crystal and an EL element is mounted on the panel substrate that holds the electro-optical substances. Mounting is done utilizing the COG (chip on glass) technology (hereafter noted as xe2x80x9cCOG mountingxe2x80x9d). This type of composition has been known. In addition, a composition has been proposed, where multiple IC chips are mounted on the panel substrate to cope with the increasingly large number of electrodes demanded by the increasing requirements for higher resolution.
FIG. 10 is a perspective drawing illustrating the composition of an electro-optical device (a liquid crystal display device in this case) equipped with multiple IC chips. As shown in the figure, this electro-optical device comprises a first panel substrate 81 and a second panel substrate 82. Each panel substrate forms an electrode on its opposing surface. They are glued together through sealing material 83. An electro-optical substance, i.e., liquid crystal, is sealed in between both substrates. The first panel 81 has an overhanging area 81a extending beyond the second panel substrate 82. A first driver IC 84 that supplies driving signals to the electrodes on the first panel substrate 81 is mounted in this area 8 la. Similarly, the second panel 82 has an overhanging area 82a extending beyond the first panel substrate 81. A second driver IC 85 that supplies driving signals to the electrodes on the second panel substrate 82 is mounted in this area 82a. 
However, when the composition shown in FIG. 10 is adopted, one or the other of the two panel substrates would extend beyond the other panel substrate, creating an overhanging area (81a and 82a). Consequently, the shape of the picture frame area of the electro-optical device, in other words, the shape of the outside area of the sealing material 83, would not be symmetrical either in the X-axis direction or in the Y-axis direction in the figure. On the other hand, the casings of electronic equipment, such as portable telephones, are frequently made laterally symmetrical. Therefore, there has been a problem in the conventional electro-optical device of not being able to fit easily into the casing of electronic equipment.
This invention was made considering the situation described above. The purpose is to present an electro-optical device having a symmetrically shaped picture frame area, an electronic equipment equipped with this electro-optical device, and a flexible substrate utilized in said electro-optical devices.
In order to solve the problems described above, in an electro-optical panel provided with pixels corresponding to the intersections of scanning lines and data lines, the substrate related to the present invention is provided with a base material, one edge of the base material is joined to the edge area of a panel substrate on which a panel IC chip for driving either the aforementioned scanning lines or data lines is mounted, and with a base IC chip that is mounted on surface of the base material and that drives either the aforementioned scanning lines or data lines.
According to this type of substrate, among the multiple IC chips driving the liquid crystal display panel, the panel IC chip is mounted on the panel substrate, and the base IC chip is mounted on the base material. Therefore, for example, it is not necessary to mount an IC chip in the neighborhood of the side adjacent to the side belonging to the edge area of the panel substrate. Consequently, the shape of the picture frame areas of the electro-optical device can be made symmetrical with respect to an axis perpendicular to the side belonging to the edge area of the panel substrate. In addition, the base IC chip is mounted on the surface of the base material containing a panel joining part. Therefore, the entire length of the wiring formed on the base material (for example, wiring between the panel joining part and the IC chip on base material) can be formed on one surface of the base material. Consequently, since it is not necessary to provide through holes penetrating the base material from one side of the base material to the other surface, the structure of the substrate can be simplified.
The substrate described above may be provided with wiring for the panel IC chip, which is formed on one surface of the base material to be connected to the aforementioned panel IC chip and which extends from the vicinity of the edge area in a direction approximately perpendicular to the edge area, and wherein the aforementioned base IC chip comprises a first IC chip mounted on one side of the aforementioned wiring for the panel IC chip and a second IC chip mounted on the other side. This way, the composition of the base material could be made laterally symmetrical, and the composition of the substrate can be simplified.
In this case, it would be desirable to have the first wiring, extending from the first IC chip to the neighborhood of the edge part, formed on one the surfaces of the base material, and the second wiring, extending from the second IC chip to the neighborhood of the edge part, formed on the same surface of the base material. According to this composition, not only the IC chips wiring on the panel, but also the entire length of the first wiring and second wiring can be formed on one surface of the base material.
In addition, it is desirable to provide an electronic parts group, which is positioned on one surface of the base material, which is mounted on the side opposite from the aforementioned edge area with respect to the aforementioned base IC chip on the base material, and which generates the control signals to be supplied to the aforementioned panel IC chip, the first IC chip, and the second IC chip; first input wiring, which is formed on one surface of the base material to connect the aforementioned electronic parts group to the aforementioned first IC chip; as well as with second input wiring, which is formed on one of the surfaces of the aforementioned substrate to connect the aforementioned electronic parts group to the aforementioned second IC chip, and wherein the aforementioned wiring for the panel IC chip is connected to the aforementioned electronic parts group. In this case, a composition having the external connection wiring, which connects the electronic parts group to the external equipment, formed on the one surface of the base material is also conceivable. This way, the entire length of all wiring, described above, can be formed on one surface of the base material.
In order to solve the problem described above, in an electro-optical panel provided with pixels corresponding to the intersections of scanning lines and data lines, the substrate related to the present invention is provided with a base material, one of whose edges is joined to the edge area of a panel substrate on which a panel IC chip for driving either the aforementioned scanning lines or data lines is mounted; with a base IC chip, which is mounted on one surface of the base material and that drives either the aforementioned scanning lines or data lines; and with an electronic parts group, which is positioned on one surface of the base material, which is mounted on the side opposite from the aforementioned edge area with respect to the aforementioned base IC chip on the base material, and which generates the control signals to be supplied to the aforementioned panel IC chip and base IC chip. In this type of composition, the shape of the picture frame area of the electro-optical device can be formed into a shape symmetrical with respect to a specific axis, for the same reason as that given above. In addition, the structure of the substrate can be simplified.
In addition, in order to solve the problem described above, the electro-optical device related to the present invention is provided with an electro-optical panel provided with pixels corresponding to the intersections of scanning lines and data lines, and for which a panel IC chip for driving either the aforementioned scanning lines or data lines is mounted inside the edge area along one side of the panel substrate, with a substrate having a base material one of whose edge is joined to the aforementioned edge area, and with a base IC chip, which is mounted on one surface of the base material to drive either the aforementioned scanning lines or data lines. In this type of electro-optical device, the shape of the picture frame of said electro-optical device could be made symmetrical with respect to a specific axis for the same reason as that given for the substrate described above.
In order to solve the problems described above, the electronic equipment related to this invention is characterized by being equipped with the electro-optical devices as described above. As mentioned above, the electro-optical device of this invention has a picture frame area shape that is symmetrical with respect to a specific axis. Consequently, it is particularly suitable for electronic equipment provided with a casing symmetrical with respect to a specific axis as a casing to accommodate said electro-optical device.